1. What is automatic identification?
Automatic identification, or auto ID for short, is the broad term given
to a host of technologies that are used to help machines identify objects.
Auto identification is often coupled with automatic data capture. That is,
companies want to identify items, capture information about them and somehow get
the data into a computer without having employees type it in. The aim of most auto-ID
systems is to increase efficiency, reduce data entry errors and free up staff to perform
more value-added functions, such as providing customer service. There is a host of
technologies that fall under the auto-ID umbrella. These include bar codes, smart cards,
voice recognition, some biometric technologies (retinal scans, for instance), optical
character recognition (OCR) and radio frequency identification (RFID).Top

2. What is RFID?
Radio frequency identification, or RFID, is a generic term for technologies
that use radio waves to automatically identify people or objects. There are
several methods of identification, but the most common is to store a serial
number that identifies a person or object, and perhaps other information,
on a microchip that is attached to an antenna (the chip and the antenna
together are called an RFID transponder or an RFID tag). The antenna enables
the chip to transmit the identification information to a reader. The reader
converts the radio waves reflected back from the RFID tag into digital information
that can then be passed on to computers that can make use of it.Top

3. Is RFID better than using bar codes?
RFID is not necessarily "better" than bar codes. The two are different technologies
and have different applications, which sometimes overlap. The big difference between
the two is bar codes are line-of-sight technology. That is, a scanner has to "see"
the bar code to read it, which means people usually have to orient the bar code toward
a scanner for it to be read. Radio frequency identification, by contrast, doesn't require
line of sight. RFID tags can be read as long as they are within range of a reader.
Bar codes have other shortcomings as well. If a label is ripped or soiled or has fallen
off, there is no way to scan the item, and standard bar codes identify only the manufacturer
and product, not the unique item. The bar code on one milk carton is the same as every
other, making it impossible to identify which one might pass its expiration date first.Top

5. Is RFID new?
RFID is a proven technology that's been around since at least the 1970s. Up to now, it's been too
expensive and too limited to be practical for many commercial applications. But if tags can be made
cheaply enough, they can solve many of the problems associated with bar codes. Radio waves travel
through most non-metallic materials, so they can be embedded in packaging or encased in protective
plastic for weatherproofing and greater durability. And tags have microchips that can store a unique
serial number for every product manufactured around the world.Top

6. If RFID has been around so long and is so great, why aren't all companies using it?
Many companies have invested in RFID to get the advantages it offers. These investments are usually
made in closed-loop systems-that is, when a company is tracking goods that never leave its own control.
That's because some existing RFID systems use proprietary technology, which means that if company
A puts an RFID tag on a product, it can't be read by Company B unless they both use the same RFID
system from the same vendor. Another reason is the price. If a company tracks assets within its own
four walls, it can reuse the tags over and over again, which is cost-effective. But for a system to
work in an open supply chain, it has to be cheap because the company that puts the tag on a case or
pallet is unlikely to be able to reuse it.Top

7. What has prevented RFID from taking off until now?
One issue is standards. There are well-developed standards for low- and high-frequency RFID systems,
but most companies want to use UHF in the supply chain because it offers longer read range-up to 20
feet under good conditions. UHF technology is relatively new, and standards weren't established until
recently. Another issue is cost. RFID readers typically cost $1,000 or more. Companies would need
thousands of readers to cover all their factories, warehouses and stores. RFID tags are also fairly
expensive-20 cents or more-which makes them impractical for identifying millions of items that cost
only a few dollars.Top

8. Are any companies using RFID today?
Yes. Thousands of companies around the world use RFID today to improve internal efficiencies. Club Car, a maker of golf
carts uses RFID to improve efficiency on its production line. Paramount Farms-one of the world's largest suppliers of
pistachios-uses RFID to manage its harvest more efficiently. NYK Logistics uses RFID to improve the throughput of
containers at its busy Long Beach, Calif., distribution center. And many other companies are using RFID for a wide
variety of applications.Top

9. What are some of the most common applications for RFID?
RFID is used for everything from tracking cows and pets to triggering equipment down oil wells. It may
sound trite, but the applications are limited only by people's imagination. The most
common applications are payment systems (Mobil Speedpass and toll collection systems, for instance),
access control and asset tracking. Increasingly, companies are looking to use RFID to track
goods within their supply chain, to work in process and for other applications.Top

10. Where will the initial benefits of RFID technology be?
RFID technology can deliver benefits in many areas, from tracking work in process to speeding up
throughput in a warehouse. Visit RFID Journal's Case Studies section to see how companies are using
the technology's potential in manufacturing and other areas. As the technology becomes standardized,
it will be used more and more to track goods in the supply chain. The aim is to reduce
administrative error, labor costs associated with scanning bar codes, internal theft, errors in
shipping goods and overall inventory levels.Top

11. How does an RFID system work?An RFID system consists of a tag made up of a microchip with an antenna, and an interrogator or
reader with an antenna. The reader sends out electromagnetic waves. The tag antenna is tuned to receive
these waves. A passive RFID tag draws power from the field created by the reader and uses it to
power the microchip's circuits. The chip then modulates the waves that the tag sends back to the reader,
which converts the new waves into digital data.Top

12. What is the difference between low-, high-, and ultra-high frequencies?
Just as your radio tunes in to different frequencies to hear different channels, RFID tags and
readers have to be tuned to the same frequency to communicate. RFID systems use many different
frequencies, but generally the most common are low-frequency (around 125 KHz), high-frequency
(13.56 MHz) and ultra-high-frequency or UHF (860-960 MHz). Microwave (2.45 GHz) is also used in
some applications. Radio waves behave differently at different frequencies, so you have to choose
the right frequency for the right application.Top

13. How do I know which frequency is right for my application?
Different frequencies have different characteristics that make them more useful for different
applications. For instance, low-frequency tags use less power and are better able to penetrate
non-metallic substances. They are ideal for scanning objects with high-water content, such as
fruit, but their read range is limited to less than a foot (0.33 meter). High-frequency tags
work better on objects made of metal and can work around goods with high water content. They
have a maximum read range of about three feet (1 meter). UHF frequencies typically offer
better range and can transfer data faster than low- and high-frequencies. But they use more
power and are less likely to pass through materials. And because they tend to be more "directed,"
they require a clear path between the tag and reader. UHF tags might be better for scanning boxes
of goods as they pass through a dock door into a warehouse. It is best to work with a knowledgeable
consultant, integrator or vendor that can help you choose the right frequency for your application.Top

14. Do all countries use the same frequencies?
Most countries have assigned the 125 kHz or 134 kHz area of the radio spectrum for low-frequency systems,
and 13.56 MHz is used around the world for high-frequency systems. But UHF RFID systems have only been around
since the mid-1990s, and countries have not agreed on a single area of the UHF spectrum for RFID. Europe uses
868 MHz for UHF, while the U.S. uses 915 MHz. Until recently, Japan did not allow any use of the UHF spectrum
for RFID, but it is looking to open up the 960 MHz area for RFID. Many other devices use the UHF spectrum, so
it will take years for all governments to agree on a single UHF band for RFID. Governments also regulate the
power of the readers to limit interference with other devices. Some groups, such as the Global Commerce
Initiative, are trying to encourage governments to agree on frequencies and output. Tag and reader makers
are also trying to develop systems that can work at more than one frequency, in order to get around the problem.Top

15. I've heard RFID can be used with sensors. Is that true?
Yes. Some companies are combining RFID tags with sensors that detect and record temperature, movement and
even radiation. One day, the same tags used to track items moving through the supply chain may also alert
staff if they are not stored at the right temperature, if meat has gone bad or if someone has injected
a biological agent into food.Top

16. How much information can an RFID tag store?
It depends on the vendor and the application, but typically a tag carries no more than 2KB
of data-enough to store some basic information about the item it is on. Companies are now
looking at using a simple "license plate" tag that contains only a 96-bit serial number. The simple
tags are cheaper to manufacture and are more useful for applications where the tag will be disposed
of with the product packaging.Top

17. What's the difference between read-only and read-write RFID tags?
Microchips in RFID tags can be read-write, read-only or "write once, read many" (WORM).
With read-write chips, you can add information to the tag or write over existing information
when the tag is within range of a reader. Read-write tags usually have a serial number
that can't be written over. Additional blocks of data can be used to store additional
information about the items the tag is attached to (these can usually be locked to prevent
overwriting of data). Read-only microchips have information stored on them during the
manufacturing process. The information on such chips can never be changed. WORM tags can
have a serial number written to them once, and that information cannot be overwritten later.Top

18. What's the difference between passive and active tags?
Active RFID tags have a transmitter and their own power source (typically a battery).
The power source is used to run the microchip's circuitry and to broadcast a signal
to a reader (the way a cell phone transmits signals to a base station). Passive tags
have no battery. Instead, they draw power from the reader, which sends out electromagnetic
waves that induce a current in the tag's antenna. Semi-passive tags use a battery to run
the chip's circuitry, but communicate by drawing power from the reader. Active
and semi-passive tags are useful for tracking high-value goods that need to be scanned
over long ranges, such as railway cars on a track, but they cost more than passive tags,
which means they can't be used on low-cost items. (There are companies developing technology
that could make active tags far less expensive than they are today.) End-users are
focusing on passive UHF tags, which cost less than 40 cents today in volumes of 1 million
tags or more. Their read range isn't as far-typically less than 20 feet vs. 100
feet or more for active tags-but they are far less expensive than active tags and can
be disposed of with the product packaging.Top

19. What is the read range for a typical RFID tag?
There really is no such thing as a "typical" RFID tag, and the read range of passive
tags depends on many factors: the frequency of operation, the power of the reader,
interference from other RF devices and so on. In general, low-frequency tags are
read from a foot (0.33 meter) or less. High-frequency tags are read from about
three feet (1 meter) and UHF tags are read from 10 to 20 feet. Where longer
ranges are needed, such as for tracking railway cars, active tags use batteries to boost
read ranges to 300 feet (100 meters) or more.Top

20. What is tag collision?
Tag collision occurs when more than one transponder reflects back a signal at the same time,
confusing the reader. Different vendors have developed different systems for having the tags
respond to the reader one at a time. These involve using algorithms to "singulate" the tags.
Since each tag can be read in milliseconds, it appears that all the tags are being read simultaneously.Top

21. What is energy harvesting?
Most passive RFID tags simply reflect back waves from the reader. Energy harvesting is a
technique in which energy from the reader is gathered by the tag, stored momentarily and
transmitted back at a different frequency. This method may improve the performance of passive
RFID tags dramatically.Top

22. What is a chipless RFID tag?
"Chipless RFID" is a generic term for systems that use RF energy to communicate data
but don't store a serial number in a silicon microchip in the transponder. Some chipless
tags use plastic or conductive polymers instead of silicon-based microchips. Other chipless
tags use materials that reflect back a portion of the radio waves beamed at them. A computer
takes a snapshot of the waves beamed back and uses it like a fingerprint to identify the
object with the tag. Companies are experimenting with embedding RF reflecting fibers in
paper to prevent unauthorized photocopying of certain documents. Chipless tags that use
embedded fibers have one drawback for supply chain uses-only one tag can be read at a time.Top

24. What is an agile reader?
An agile reader is one that can read tags operating at different frequencies or using different
methods of communication between the tags and readers.Top

25. What are intelligent and dumb readers?
These terms are not precise, but many people use "intelligent reader" to describe one
that has the ability not just to run different protocols, but also to filter data and
even run applications. Essentially, it is a computer that communicates with the tags.
A "dumb" reader, by contrast, is a simple device that might read only one type of tag
using one frequency and one protocol. This type typically has very little computing power,
so it can't filter reads, store tag data and so on.Top

26. What is reader collision?
One problem encountered with RFID is that the signal from one reader can interfere with the signal
from another where coverage overlaps. This is called reader collision. One way to avoid the problem
is to use a technique called time division multiple access, or TDMA. In simple terms, the readers are
instructed to read at different times, rather than both trying to read at the same time. This ensures
that they don't interfere with each other. But it also means any RFID tag in an area where two readers
overlap will be read twice. So the system has to be set up so that if one reader reads a tag, another
reader does not read it again.Top

27. What is "dense reader" mode?
This is a mode of operation that prevents readers from interfering with one another when many are used
in close proximity to one another. Readers hop between channels within a certain frequency spectrum
(in the United States, they can hop between 902 MHz and 928 MHz) and may be required to listen for a
Signal before using a channel. If they "hear" another reader using that channel, they go to another
channel to avoid interfering with the reader on that channel.